1 Department of Clinical Research, University of Basel, Basel, Switzerland; Department of Visceral Surgery, Clarunis University Centre for Gastrointestinal and Liver Diseases, St. Clara Hospital and University Hospital Basel, Basel, Switzerland.
2 Department of Gastroenterology, University Hospital, Zurich, Switzerland; Laboratory and Clinic for Motility Disorders and Functional Digestive Diseases, Klinik Arlesheim, Arlesheim, Switzerland.